This invention relates to the area of heat or cold management systems and, specifically, to the heat or cold management systems, which include application of phase change materials (PCM).
The main field of usage of these heat or cold management systems is thermal solar power plants that apply some types of optical concentrators of solar radiation in order to achieve sufficiently high temperature of heat transfer medium flowing in the receiver of a solar collector. However, the proposed heat management system can be used in other fields, for example, for decrease of energy consumption in thermal treatment of metals.
Another important application of the proposed heat or cold management system is cold accumulation in the form of ice in large air-conditioning systems in night-time.
It is known, that heat or cold can be stored in materials in the forms of sensible heat or latent heat. A material storing sensible heat can be in liquid form (for example, water, molten salts) and a bed of solid material (for example, concrete or ceramic packing, river rocks). The bed serves as well as a heat exchanging structure.
Heat or cold storage in the latent form is performed usually by phase changes: solid-solid, solid-liquid or solid-liquid accompanied by chemical reactions (in the most cases, by reaction: dehydration-hydration).
This invention proposes a heat management tower with a packing, which can be related to solid-liquid phase change.
It should be noted, that phase-change storage allows to achieve high energy density with resulting economical advantage. Design of a phase-change storage container must provide appropriate technical solutions to problems of poor heat transfer of a phase-change material (PCM), corrosion, possible chemical reaction between the PCM and a heat transfer fluid (HTF), possible change of the PCM volume in the process of the phase change.
Technology of micro- and macro-capsulation is widely used in the modern practice in order to solve these problems.
However, this technology is very expensive and resulting specific cost of stored thermal energy is usually high.
There are some U.S. patents related to the area of heat or cold storage with application of PCM.
U.S. Pat. No. 4,086,958 describes heat exchange method and an apparatus, which are based on direct contact of two non-mixable media. Thermal contact of these media is performed by bubbling the liquid medium through the second medium, when the second medium is in the liquid phase.
U.S. Pat. No. 4,088,183 proposes a thermal energy storage housing that is designed like as a shell-and-tube heat exchanger.
U.S. Pat. No. 4,111,260 describes a thermal accumulator, which is designed as a closed vessel with a set of horizontal trays filled with PCM, when HTF flows across the outer surfaces of the PCM layers in the trays. This construction requires application of special means for holding the PCM in these trays.
U.S. Pat. No. 4,270,523 describes a heat storage apparatus with a plurality of heat exchanging elements mounted in a housing.
Each element has a central portion containing a storage medium, surrounded by portions through which a first and a second heat transfer fluids can be passed in heat contact with the storage medium.
U.S. patent application No. 20020000306 describes a device and method for storing thermal energy. The proposed device comprises: a) a container having inlet and outlet ports and at least one wall; b) at least one cell, this cell having two lateral sides and being placed within the aforementioned container such that the lateral sides of the cell are separated from the wall of the container; and c) at least one phase change material being capable of undergoing a phase change at a functional temperature above melting point of water at one atmosphere or pressure, this phase change material being disposed within the aforementioned cell.
In addition, U.S. Pat. Nos. 4,371,029, 4,807,696 and 6,116,330 should be noted. However, these patents do not provide a construction of a heat or cold storage, which is based on usage of ceramics or glass containers for their filling with PCM.
The article of Peter R. Payne “WHICH MATERIAL USES THE LEAST ENERGY?” (CHEMTECH, September 1980, pp. 550÷557) demonstrates importance of application of ceramics in construction of solar collectors as a low-energy-cost material. Conclusions of this article are true for the case of construction of heat or cold storage plants.